在 Numpy 中返回指定的对角线并设置对角线相对于主对角线的偏移量

要返回指定的对角线，请在 Numpy 中使用 **ma.MaskedArray.diagonal()** 方法。设置对角线相对于主对角线的偏移量。可以是正数或负数。

掩码数组是标准 numpy.ndarray 和掩码的组合。掩码要么是 nomask，表示关联数组的任何值均无效，要么是布尔数组，用于确定关联数组的每个元素的值是否有效。

步骤

首先，导入所需的库 -

import numpy as np
import numpy.ma as ma

使用 numpy.array() 方法创建包含整数元素的数组 -

arr = np.array([[55, 85, 59, 77], [67, 33, 39, 57], [29, 88, 51, 37], [56, 45, 99, 85]])
print("Array...
", arr)
print("
Array type...
", arr.dtype)

获取数组的维度 -

print("
Array Dimensions...
",arr.ndim)

创建一个掩码数组并将其中一些标记为无效 -

maskArr = ma.masked_array(arr, mask =[[1, 1, 0, 0], [ 0, 0, 1, 0], [0, 0, 0, 1], [0, 1, 0, 0]])
print("
Our Masked Array
", maskArr)
print("
Our Masked Array type...
", maskArr.dtype)

获取掩码数组的维度 -

print("
Our Masked Array Dimensions...
",maskArr.ndim)

获取掩码数组的形状 -

print("
Our Masked Array Shape...
",maskArr.shape)

获取掩码数组的元素数量 -

print("
Elements in the Masked Array...
",maskArr.size)

返回指定的对角线，在 Numpy 中使用 ma.MaskedArray.diagonal() 方法。设置对角线相对于主对角线的偏移量。可以是正数或负数。默认为主对角线 (0) -

print("
Result...
",maskArr.diagonal(2))

示例

# Python ma.MaskedArray - Return specified diagonals and set the offset of the diagonal from the main diagonal

import numpy as np
import numpy.ma as ma

# Create an array with int elements using the numpy.array() method
arr = np.array([[55, 85, 59, 77], [67, 33, 39, 57], [29, 88, 51, 37], [56, 45, 99, 85]])
print("Array...
", arr)
print("
Array type...
", arr.dtype)

# Get the dimensions of the Array
print("
Array Dimensions...
",arr.ndim)

# Create a masked array and mask some of them as invalid
maskArr = ma.masked_array(arr, mask =[[1, 1, 0, 0], [ 0, 0, 1, 0], [0, 0, 0, 1], [0, 1, 0, 0]])
print("
Our Masked Array
", maskArr)
print("
Our Masked Array type...
", maskArr.dtype)

# Get the dimensions of the Masked Array
print("
Our Masked Array Dimensions...
",maskArr.ndim)

# Get the shape of the Masked Array
print("
Our Masked Array Shape...
",maskArr.shape)

# Get the number of elements of the Masked Array
print("
Elements in the Masked Array...
",maskArr.size)

# To return specified diagonals, use the ma.MaskedArray.diagonal() method in Numpy

# Set the Offset of the diagonal from the main diagonal. Can be positive or negative.

# Defaults to main diagonal (0).
print("
Result...
",maskArr.diagonal(2))

输出

Array...
[[55 85 59 77]
[67 33 39 57]
[29 88 51 37]
[56 45 99 85]]

Array type...
int64

Array Dimensions...
2

Our Masked Array
[[-- -- 59 77]
[67 33 -- 57]
[29 88 51 --]
[56 -- 99 85]]

Our Masked Array type...
int64

Our Masked Array Dimensions...
2

Our Masked Array Shape...
(4, 4)

Elements in the Masked Array...
16

Result...
[59 57]

AmitDiwan

更新于: 2022 年 2 月 2 日

219 次查看

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